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Fireplace Insert Buying Guide

Fireplace Insert Buying Guide

Do you want to upgrade your existing fireplace to be more efficient and convenient?  Fireplace inserts are perfect for homeowners who have a traditional fireplace but are looking for something with more features. With various styles and fuel types, the options are almost endless.

Fireplace Insert Buyer's Guide
Superior direct vent gas fireplace

This will be your comprehensive overview of what is available, how to choose the right insert for your home, brand recommendations, and maintenance tips.

What is a Fireplace Insert?

A fireplace insert is a closed-combustion firebox installed into an existing fireplace to increase efficiency. Inserts are usually designed for existing masonry fireplaces, although some manufactured fireplaces also accept them. Depending on the type of fuel you wish to use, there are several categories to choose from.

Please note that a prefabricated zero clearance fireplace is not the same as a fireplace insert. Zero clearance fireplaces framed into a wall or mantel cabinet, while fireplace inserts require an existing fireplace.

Occasionally, you will find a fireplace insert model that can be installed in either a framed opening or an existing fireplace. However, for our purposes, we will use the term "fireplace insert" to refer only to an appliance that must be installed within an existing fireplace.

Types of Fireplace Inserts

Fireplace inserts are typically categorized by the type of fuel they burn. You can choose from wood burning, pellet, natural gas, propane gas, or electric fireplace inserts. The fuel type determines your venting options, as well as the overall operation of the insert. You can choose from vent-free, direct vent, and natural vent options for gas fireplace inserts.

Fireplace Insert Buyer's Guide
US Stove Corn and Pellet-Burning Fireplace Insert

Fireplace Inserts vs. Traditional Fireplaces

One of the main advantages of fireplace inserts is that they offer better heating efficiency. Traditional, open-faced fireplaces could be more efficient when heating a room. Fireplace inserts burn fuel better and maximize the heat that radiates to the room, wasting less fuel and heat loss to the chimney.

Their high-efficiency design cuts down on fuel and utility costs. They also offer better air quality because little to no smoke is released into the room.

Fireplace Insert Buyer's Guide
Empire Direct Vent Gas Fireplace Insert

Another bonus is that they do not take up additional floor space. Instead, an insert upgrades the fireplace you already have. Depending on the type of insert, you can install them almost anywhere. Many models are rated for bedrooms, bathrooms, and even mobile homes. However, there are a few other issues to consider.

For one, the sealed front of the inserts somewhat limits flame visibility. They also require an existing fireplace and tend to be smaller in size. Also, although a few more modern styles exist, most options are limited to a traditional aesthetic.

If you want big, open, crackling flames or the ability to put a fireplace anywhere, there are better options than an insert. However, fireplace inserts are perfect if you want to upgrade your existing fireplace or want a versatile, low-maintenance, and more efficient replacement.

How to Choose the Right Fireplace Insert

When choosing a fireplace insert, you must consider three main factors: the size of the existing fireplace, the type of fuel you want, and your venting preferences. Once you outline your preferences and limitations in those three categories, you'll have a clearer idea of what model will work best for you.

Measure the Size of Your Existing Fireplace
Fireplace Insert Buyer's Guide
White tape measurer

Start by measuring the dimensions of the existing fireplace, including the width and height of the front and back of the fireplace. Sometimes, fireplace openings taper, meaning the opening at the front is bigger than the width and height of the back of the fireplace. You'll also need to measure the depth of the fireplace.

Fireplace Insert Buyer's Guide
Measuring for a fireplace insert infographic

Fireplace inserts fit inside a range of fireplace sizes. They come with a metal surround that acts as a frame and covers the gap between the insert and the fireplace's opening. If the opening is too small, the insert will not fit, and if it is too large, the surround will not be wide enough to cover the gap between the fireplace insert and the opening of the existing fireplace.

Most fireplace inserts are designed for traditional masonry fireplaces (i.e., fireplace openings made from masonry materials like stone or brick). Finding an insert for a manufactured fireplace is more difficult. Many manufacturers forbid using fireplace inserts with their fireplaces or limit the inserts to certain approved prefabricated models.

Take note of any other aspects of the existing fireplace. Is it on an outside wall? Does it have a functional chimney? This will help you know your limitations when you move on to choosing the right fuel.

Choose Your Fuel and Vent Type

Fuel options for your fireplace insert include wood, pellet burning, natural or propane gas, and electric. Your fuel will determine whether you need gas lines, power outlets, venting, and other installation requirements your insert will need.

Wood Burning Fireplace Inserts

Wood burning fireplace inserts function like a wood stove. They use a flexible or rigid vent liner that routes into the existing chimney. Flexible venting is the most commonly selected method for wood burning inserts and must be a minimum grade of 304 stainless steel, with 316 stainless being preferred.

Flexible liners must meet the requirements of the insert manufacturer and be rated to the UL1777 standard. Typical flexible liner installations will consist of a rigid appliance adapter with a separate or integral gear clamp, the flexible liner itself, a top support plate with a clamp, and a cap and storm collar.

The other installation type for wood burning insert venting is rigid liners. While more costly, the rigid liner sections are typically factory-insulated and seal very well. The sections will either screw together or utilize a lance and dimple system. Quite literally, think of how a Swiffer mop assembles; you match the two pieces together, slide one into the other, and twist to lock it in.

Even if the system does utilize the twist and lock system, at least one screw per section should be used to ensure the liner sections do not separate in the event of a rotation of the liner or, even worse, in the event of a chimney fire. A rigid chimney liner is more challenging than a flexible one since you cannot simply cut off the excess. Exact measurements for each portion of the liner routing must be taken. The liners must also compensate for offsets, narrow areas, and a specialized termination at the top of the chimney.

To summarize, rigid liner systems require more planning than flexible systems, but they eliminate the need for field-installed insulation and are more durable than their flexible counterparts.

Many require a liner for the full length of the chimney. Wood burning fireplace inserts are a good option if you wish to continue using wood for fuel but want a more heat-efficient appliance. However, they require more effort to operate and maintain than the other fuel options.

Fireplace Insert Buyer's Guide
Napoleon EPA Wood Burning Fireplace Insert

Unlike masonry wood burning fureplaces, Wood burning stoves and inserts are subject to EPA efficiency standards. Current EPA regulations specify that stoves must produce less than 2.5 grams of smoke per hour. Unfortunately, there is a slight increase in the cost of the stoves, but the improved efficiency saves money on fuel, making it a trade-off.

While wood stove inserts have an edge on efficiency over wood fireplaces, you can't guarantee that having a wood insert will be more cost-efficient. The savings of wood over gas heating can vary. If you buy your firewood in the offseason, you will get lower prices for your wood. If you buy the firewood as you need it, prices may double.

One of the major disadvantages of wood-burning appliances is rising appliance operating costs. From the cost of the unit itself, which has increased as the overall efficiency rating has changed, rising costs of lumber have changed the overall pricing of owning a wood burning stove.

The cost of a wood-burning fireplace insert, including the purchase, installation, and necessary venting, can range from $3,200 to $10,800, with an average of $ 4,000. This range covers both the venting and installation costs and the cost of the inserts themselves.

The lower end of the range assumes that the receiving fireplace is in good condition and that the chimney and fireplace only need a chimney cleaning before installation. It also assumes that the chimney is the correct height, is roughly 15 feet (of 304 flex liner with crimp seams) in length, and will be easily terminated using no custom parts. Meanwhile, the higher end of the range assumes the fireplace and chimney need some maintenance; the termination might need some custom fabrication and up to 30-35 feet of 316 alloy liner with welded seams for the chimney.

Pellet Stove Inserts

A pellet fireplace insert functions like a pellet stove, burning small compressed pellets of wood biomass as fuel. In addition to a chimney for the flexible vent liner, pellet stove inserts also require an electrical power source. The electricity used to power fans and pellet feed augers within pellet fireplace inserts offers some automation and control over the fire's heat output. Thermostatic controls can be set to maintain the desired temperature range.

Fireplace Insert Buyer's Guide
Napoleon 45-Inch Black Pellet Stove Insert

A pellet stove insert uses a flexible vent liner that runs from the vent collar on the unit up through the chimney. We recommend installing a cleanout tee near the flue collar of the insert so that you can clean out the liner without taking apart the entire vent structure.

Pellet inserts are easy to operate but require more maintenance than gas or electric models. Pellet heating is a fraction of the cost of a gas system. Compared to wood burning, pellet heating is cleaner burning and far more efficient than wood or gas heating by a mile.

Pellet fuel is manufactured for the intended purpose of providing efficient heating. It is quality controlled and tested, with the final product being prepackaged bags with a label showing what is inside, so pellet fuel does not offer the variables to consider with even the best wood burning practices. A pellet-burning insert utilizes pellets for fuel, fed to the fire by an automatic auger; as such, they require electricity to operate. However, some models have a backup battery feature to allow operation during a power outage. Pellets are harder to find than other fuel sources but are becoming more common.

With pellet systems, venting is more complex than taking a rough measurement of the total height of the chimney, ordering more than needed, and simply cutting away what isn't used. This type of venting depends on the liner you choose. Suppose you choose to use a chimney liner to vent your pellet insert. In that case, they are typically approved to use a 4" diameter chimney liner that is stainless steel and listed to UL 1777, the same listing for liner used when relining a chimney for use with a wood insert.

If you choose to go this route, it is straightforward & involves ordering more than needed and cutting away what you do not use. You have to use no manufacturer-specific liner brands, so long as the proper diameter is used; the liner is listed to UL 1777 and constructed of stainless steel.

If you were to choose a Type PL pellet system, there is no flexible stainless steel liner to cut. Type PL venting is offered with flexible stainless sections, but each end of this liner commonly has a twist lock section for connecting to PL venting with these same twist lock connections. This typically 10' section is meant to pass through the damper and smoke shelf to reach the vertical chimney where rigid twist lock sections extend to the top of the chimney, so pretty accurate measurements are needed. Adjustable lengths are available to accommodate any measurement.

The cost of a pellet-burning fireplace insert, including the purchase of the insert, the installation, and the necessary venting, can run from $5,000 to $6,100. This range is mostly in the installation due to the electrical needs. The lower end of the range assumes that the existing fireplace and chimney are in good condition and that an electrical source is nearby. The lower end of the range also assumes that the chimney does not need to be lengthened and that you need only up to a 15-foot run of 3-inch 304 alloy stainless steel chimney liner.

The higher end of the range includes the need for electrical relocation to power the insert, service to the existing fireplace and chimney, and the possibility of an outside air kit to be installed. The higher end of the range also assumes you would use up to a 35-foot run of a 4-inch venting system.

Gas Fireplace Inserts

Gas fireplace inserts require a gas line to accept propane or natural gas. If you do not have an existing gas hookup for the fireplace, you will need to hire a professional plumber to run a line for you. Most models also require an electrical power source. Choose from vent-free, direct vent, and natural vent options for venting the appliance.

The cost of a gas fireplace insert, including the purchase of the insert, the installation, and any necessary venting, can run from $3,200 to $6,600. The cost of gas fireplace inserts can vary wildly due to installation costs.

The lower end of the range assumes that your existing fireplace is in good condition, you already have the gas line to it, and that you are installing a vent-free unit that won't require any venting components. The upper end of the range assumes a direct vent gas insert that will require a co-linear vent system to be installed, possible custom termination flashing or modifications, and routing of a gas line from existing gas infrastructure within the home.

Fireplace Insert Buyer's Guide
Real Fyre mSeries Direct Vent Gas Fireplace Insert

We recommend getting a price quote to estimate the costs of running a new gas line or extending an existing one. Ensure the insert you use is designed for the type of gas you intend to use.

If you need more information to help you understand the differences between natural gas and propane, click here to read this article. It explains the differences between the two gases, tells which gas is best for certain situations, and describes the process for converting from one gas to the other.

Vent-free gas models do not need outside venting. Instead, they rely on room air for oxygen and vent the tiny amount of smoke they produce back into the room. Vent-free inserts are convenient, but check to ensure they are allowed where you live since they are restricted in some areas. They are also not recommended for anyone with air sensitivities.

Direct vent gas inserts are completely sealed from the room and exchange combustion air through the outdoor venting system. This makes them a good option for anyone especially concerned with air quality since none of the smoke produced ever enters the room. Many direct vent gas fireplace inserts have blowers or electronic ignitions that require electricity. So, check that you have an outlet nearby if you choose a direct-vent option.

Direct vent gas fireplaces use a rigid coaxial vent pipe with a small pipe within a larger pipe. The small pipe vents the exhaust gases, and the larger pipe draws in outside air for combustion.

However, a direct vent gas fireplace insert is designed to vent through the chimney of the existing fireplace. Instead of a rigid coaxial pipe, the inserts use two flexible liners called co-linear vent pipes that run side by side up the chimney. One liner draws in air from outside, and the other expels the exhaust gases.

Direct vent inserts are also an excellent choice for customers with homes retrofitted with very tight insulation, resulting in a limited amount of oxygen to supply a naturally drafted system. A solid pane of tempered or ceramic glass seals the combustion chamber, and since all combustion air is drawn in from the outdoors and all combustion gases are exhausted to the outdoors, there is zero air exchange with the home.

If an existing leaky hearth is causing heating costs to rise, adding a direct vent gas insert can eliminate this headache. Direct vent inserts also release minimal emissions into the atmosphere for those who are environmentally conscious and are safe to install in every state and province. 

Unlike direct vent gas inserts, natural vent (b-vent) gas fireplace inserts are not sealed to the room. They require a chimney liner for venting, much like a traditional wood burning fireplace. Not all models require an electrical outlet but always check to make sure you have one if it is needed. These units are mostly used for aesthetics since they have tall, beautiful flames but are less heat efficient.

Electric Fireplace Inserts

Electric fireplace inserts are the most versatile option. They do not require venting or gas lines and can be installed almost anywhere. The only consideration is the electrical supply. The flame technology of electric models has improved greatly, producing a lovely, realistic fire display. The inserts can come with or without a heating component Click here to learn more detailed information about electric fireplace inserts, including the types available, the proper ways to install and clean them, and a list of some top manufacturers.

Fireplace Insert Buyer's Guide
Dimplex electric fireplace insert

Leading Brands

  • Kingsman - This manufacturer is notable for pioneering gas-fueled fireplaces and inserts in the hearth industry. With modern products featuring exclusively gas-fueled operation, Kingsman fireplace inserts offer considerable customization options at a price that many can afford. In many cases, several decorative overlays, surrounds, and media options are available for a single insert, allowing the consumer to tailor the appliance to their needs.
  • Napoleon - It isn't easy to find a more all-inclusive product lineup than Napoleon products. Realizing early on that the best way to build a strong company was to build something for everyone, Napoleon offers inserts in wood burning, gas, electric, and pellet fueled models. Their models are built to high standards, constantly evolving and improving based on real-world needs.
  • Quadra-Fire - A long-time manufacturer of high-quality hearth products, Quadra-Fire offers consumers a limited but handsome-looking assortment of wood, gas, and pellet-fueled inserts. Their products are timeless and built to a level of quality that makes them stand out.
  • Dimplex - Unmatched in quality or variety, Dimplex manufactures one of the industry's widest range of electric fireplaces and inserts. Well-known as an early player in electric fireplace technology, Dimplex continues to lead the industry in electric flame realism. They offer a range of products that can be installed like an insert, giving consumers an alternative to gas and wood-fired options.
Fireplace Insert Buyer's Guide
Types of fireplace inserts infographic

How to Install Fireplace Inserts

There are four basic phases of any fireplace insert installation. The first is the planning stage, which involves finding the right model and planning the installation. The next stage is the prep work to prepare the existing fireplace for the insert. The last two stages are installation and inspection, which involve installing and testing the insert to ensure it works properly.

Phase I: Planning
Fireplace Insert Buyer's Guide
Two male contractors at an installation site

As mentioned in the section on choosing the right insert, finding an appropriately sized unit is key. Depending on the type of fuel you choose, fireplace inserts fit a range of openings. Whether you choose to install yours into the opening of existing fireplaces or an opening in a framed wall structure, measure the installation location carefully and double-check that the unit you buy will fit. Once you decide on your fuel preference and size limitations, you can begin planning for the venting components and provisions for a gas line installation.

We recommend hiring a professional to run gas lines or install electrical outlets. Ideally, the electrician will install a recessed outlet behind the fireplace insert. This keeps cords from trailing out from the unit to nearby power outlets. It's usually best to have a power supply on a dedicated circuit, but this depends on the appliance type.

Purchase all the appropriate venting components, including chimney liners. If you are converting from one fuel supply to the other, buy the conversion parts you will need.

Phase II: Prep Work
Fireplace Insert Buyer's Guide
Fireplace prep for insert installation

The prep work involves any fuel conversion and preparation of the existing fireplace. If the fireplace has a damper, you will likely need to remove it to make room for the chimney liner. Masonry fireplace openings often have rough edges that must be smoothed so the surround of the insert can sit flush against the front of the fireplace.

The edges can be smoothed with a grinder if the fireplace is stone or brick. However, don't use a grinder on material that shatters easily (such as slate). Instead, screed a small layer of cement around the opening to create a smooth edge.

Wood to Gas Conversion

Have a plumber install a gas line for the new fireplace insert. The components required for fireplace inserts differ slightly depending on whether they use natural gas or propane. Ensure the model you buy is rated for the type of gas you intend to use. You will likely need a 120-volt power supply as well.

Always read your owner's manual for details on your specific model. The manufacturer will specify what the appliance requires regarding the power supply, installation restrictions, and maintenance.

Gas to Wood (or Pellet) Conversion

Remove the gas log lighter and seal the gas supply line. This must be done properly to ensure safety. We recommend hiring a professional plumber to remove gas components and seal the gas lines. You must also remove the chimney damper and make sure that there is sufficient venting for the wood-burning fire.

A wood stove insert may or may not need a power supply, but all pellet stove inserts require one to run the fuel auger and blowers.

Wood or Gas to Electric Conversion

Electric fireplace inserts do not need venting, so close off the chimney flue and damper. Remove any gas lighters or log sets and properly seal off the gas lines. Hire an electrician to install a recessed outlet behind the electric insert to keep the cords hidden. You can use a nearby outlet if a recessed outlet is not an option.

Fireplace Insert Buyer's Guide
Coverting fuel for fireplace inserts infographic
Phase III: Installation
Fireplace Insert Buyer's Guide
Two men delivering a shipment

Many fireplace inserts are heavy, so enlist extra help lifting the unit into place. Start by assembling the venting. Hook up any gas lines or power supply to the unit. Fit the insert into place and mount the surround around the unit using the included hardware. The surround should sit flush with the fireplace opening. Remember to add new veneer facing around the perimeter of your fireplace opening if the old one no longer works!

Please read the instructions for your unit before starting the installation. The installation may vary slightly depending on the model type.

Phase IV: Inspection
Fireplace Insert Buyer's Guide
Gas pressure meter

Inspection is a critical part of ensuring the safety of your new fireplace insert. We'll review inspection tips for each of the main categories of fireplace inserts. If you have any concerns about how your fireplace insert is operating, please call the manufacturer or one of our NFI Certified technicians.

Fireplace Insert Buyer's Guide
Phases of fireplace insert installation infographic

How to Inspect a Fireplace Insert

  • Start the initial kindling fire and watch to see that smoke is drawn to the vent liner and does not spill into the room.
  • Once fuel logs are added and burning, close the door. Verify that you can control the burn rate by adjusting the air control handle between the high and low burn settings.
  • During operation, inspect for smoke leaks around the door gasket. Check that the doors close and latch properly.
  • If equipped with an outside air kit, test to see if it operates as it should.
  • Complete an external inspection of the chimney to make sure the smoke exits properly and does not pool at the chimney termination.

How To Inspect Pellet Stove Inserts

  • When first starting the unit, test the control board to see if the system responds properly.
  • Listen to the pellet feed auger. It should sound relatively quiet and consistent.
  • Check that the auger drops a metered amount of pellets into the burn pot. It should not over- or underfill the pot.
  • Monitor the burn pot to see if the igniter is lighting the pellets and if combustion air is helping them burn evenly.
  • Watch for any smoke leaks from the glass front or the appliance back.
  • Please verify that the convection blower cycles on when it should and that heat is emitted into the room. If the fan has a manual adjustment, check that all the speed settings work.
  • There should not be any smoke smell in the home when the unit is operating.

How To Inspect Vented Gas Fireplace Inserts

  • During initial use, check that the pilot light ignites and remains stable before igniting the main burner.
  • Monitor the main burner ignition. The sequence should be controlled and not sudden or violent.
  • Watch the flame pattern. Look for burner ports with no flame or overly sooty or blue flames. If the flame pattern appears incorrect, verify the air shutter is set properly. (The manufacturer will have instructions for these adjustments.)
  • If equipped with a fan, test it to ensure it cycles as it should.
  • When first used, gas appliances release an odor that smells like burning paint. Odd smells should not linger after using the unit for more than 4 hours.

How To Inspect Vent-Free Gas Fireplace Inserts

  • Vent-free gas models follow the same inspection rules as vented gas models.
  • However, there is an additional step. You'll need to check that the flame is not blocked by a log and that the unit does not emit acrid odors.

How To Inspect Electric Fireplace Inserts

  • Inspect the unit to see that the backlighting and other lighting features work.
  • Verify the heating element operates and that the fan-forced heat can be felt in the room (if applicable).
  • Listen for odd sounds such as clicking or grinding.
  • An odor of hot metal will be present initially but should dissipate within an hour.
  • Verify the remote and other controls all function as designed.

Fireplace Insert Maintenance Tips

Fireplace Insert Buyer's Guide
Vacuuming the firebox with a brush hose

The owner's manual will contain specific instructions for the care and maintenance of your specific model. Wood and pellet fireplace inserts require the most frequent maintenance. Gas and electric models are easier to maintain but should still be cleaned and inspected regularly.

Wood and Pellet

Always use the proper fuel for wood or pellet stoves. Do not burn trash or any unauthorized fuel since this can lead to harmful creosote buildup. Clean out the ash regularly according to the instructions. Schedule a yearly inspection to ensure all components are working safely.

If you installed a cleanout tee on your pellet insert, periodically sweeping out the vent liner should be easier. Remove the surround and gently pull the unit forward. Detach the cover of the cleanout tee to sweep the liner.

Vented and Vent-Free Gas Models

Have a certified professional inspect the unit yearly to ensure everything is in working order. Periodically vacuum the components to prevent dust buildup. Do this gently so you don't damage any parts. The glass can be cleaned with a soft cloth and a water-based cleanser.

Electric Models

Electric models require the least amount of maintenance. Monitor the electrical wires to ensure they are not frayed or chewed. This is especially important if you have rodents near your area. Vacuum the unit to prevent dust from building up on the fan or other components. You can wipe down the glass periodically.


Small, lightweight fireplace inserts can be shipped via small parcel post. Larger units will require LTL carrier shipping. Always inspect the unit when it arrives for damage or missing parts. Contact the manufacturer immediately if you notice anything amiss.


Fireplace inserts breathe new life into old, inefficient fireplaces. Whether you opt for wood-burning, gas, or electric, you can find a model that fits your space and meets your needs. The range of options for fireplace inserts is quite broad. So, focus on your main priorities for your space to help you narrow down the best option.

As always, reach out to us with any questions! Our NFI Certified Technicians are available to help!

About the Author

Collin Champagne

With over 13 years in the industry, Collin is a National Fireplace Institute (NFI) certified technician and managed content for the eFireplacestore and eCanopy brands. He has achieved the highest NFI certification possible as a Master Hearth Professional and is certified in all three hearth appliance fields: wood, gas, and pellet. With experience with sales and in-field installations, his expertise shines through his technical knowledge and way with words.

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